French newspaper Le Parisien has revealed the fates of four of the main protagonists in the final instalment of the Harry Potter book series.

The daily printed a three-paragraph summary of the book's epilogue upside down so readers could choose to ignore revelations about characters, whose survival was thrown into doubt after author J.K. Rowling said she intended to kill off two characters and gave one a reprieve.

Harry Potter and the Deathly Hallows hits the shelves at a minute past midnight Saturday in a carefully orchestrated release designed to maximise suspense and sales from London and New York to Mumbai and Australia's Outback.

Plot details -- including the fate of the boy wizard and his Hogwarts friends -- have been closely guarded secrets which have mostly survived intact despite a pre-publication review in some major newspapers which have earned Rowling's ire.

But the book's release has been marred by leaks of its contents on the Internet, both real and fake, and by a mistake made by an online U.S. retailer that meant a small number of hard copies were sent to buyers days ahead of publication.

Rowling reacted angrily when two U.S. newspapers ran reviews on Thursday based on copies they obtained ahead of publication.

I am staggered that some American newspapers have decided to publish purported spoilers in the form of reviews in complete disregard of the wishes of literally millions of readers, particularly children, the 41-year-old said.

Potter publishers will take comfort from the fact that the majority of fans do not know what happens in book seven, and do not want to until they get their hands on a copy on what has been dubbed in the media as P-Day.

The first six books in the series, which began with Harry Potter and the Philosopher's Stone in 1997, have sold 325 million copies and the first five movies in the film franchise have amassed around $4 billion at the global box office.